China has retaliated on both occasions with tariffs on the equivalent value of US goods.

The Chinese imports targeted so far include a vast range of goods, including semiconductors, plastics, chemicals and railway equipment, and fridges. The US products targeted by China include coal, copper scrap, fuel, buses and medical equipment.

If a third set of tariffs on $200bn worth of Chinese goods are imposed then a host of tech firms have warned they will be impacted.

Apple is reported to have told the US government it will affect the cost of its Apple Watch, AirPods, HomePod, AirPort routers, Apple Pencil, Mac mini, and some adapters/cables, according to Bloomberg.

The firms are worried the tariffs will increase their costs since many of their components come from China.

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The escalating dispute between the US and China dates back to January

Mr Trump says he wants to stop the "unfair transfers of American technology and intellectual property to China" and protect jobs.

Tariffs, in theory, will make US-made products cheaper than imported ones, so encourage consumers to buy American. The idea is they would boost local businesses and support the national economy.

But many US companies and industry groups have testified to the US Trade Representative's Office that their businesses are being harmed.

The dispute dates back to January, when the US slapped controversial tariffs on imported washing machines and solar panels. That was considered Mr Trump's most significant trade move since his decision to pull the US out of the TPP and renegotiate the North American Free Trade Agreement (Nafta).

The US imported $505bn in goods from China last year, and this year until the end of July, Chinese imports are nearly 9% higher, according to official US data.

Earlier, White House economic adviser Larry Kudlow told CNBC that the administration was still talking with China about trade issues but that so far China had not met US requests.